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mikejuk writes with this excerpt from I Programmer: "A movie that features science and technology is always welcome, but is it not often we have one that focuses on computer science. Travelling Salesman is just such a rare movie. As you can guess from its name, it is about the Travelling Salesman problem, more precisely about the P=NP question. Written and directed by Timothy Lanzone, and produced by Fretboard Pictures, it should premiere on June 16. As the blurb to the movie trailer says: 'Travelling Salesman is an intellectual thriller about four of the world's smartest mathematicians hired by the U.S. government to solve the most elusive problem in computer science history — P vs. NP. The four have jointly created a "system" which could be the next major advancement for humanity or the downfall of society.'"

I'll hold off a bit on that. However once I hear hipsters using it in casual conversations at parties, or new age psychics explaining their abilities with it, then I'll know that P=NP is the new string theory.

Aquaman: "We'll never catch The Traveling Salesman! Not even the Bat Computer can match the efficiency of his route!"Superman: "Unless we can enhance the Bat Computer by using my Super Spinning to change the vibrations of space in the area..."Batman: "... to duplicate The Traveling Salesman's powers! It just might work!"

It's highly likely that somebody will eventually be able to prove it to be true or false. (The current thinking is that it's probably false, given the number of smart people who've been looking for it, but we could be surprised.) This isn't one of those "Gödel says this statement isn't a lie" sorts of problems, nor is it likely to be a "Proof won't fit in a single human brain" problem. And unless Charlie Stross is right, it's not even one of those "Maths that are too dangerous for mere mortals to m

Since when is cryptography NP? Cracking any encrypted message takes a well-defined amount of time, derived from available computing power and the length and complexity of the key. Faster computers will help you here. Better factoring algorithms may help you here. But P=NP will not help you crack anything.

NP can also take a well-defined amount of time, it is not the point of it. But you are absoluelly right, that factorisation algorithms do not have anything to do with P=NP, since the problem is not proven to be NP-complete.

Factoring is NP, since we can verify the results in polynomial time. It's not NP-complete, so finding a polynomial algorithm for factoring doesn't necesarily mean that there's one for 3-SAT or TSP, but if we find a polynomial algorithm for TSP, then there is one for factoring.

It means there should be, in theory, an algorithm that is substantially better than exponential explosion, which, in the case of long-number, almost-prime cryptography, means something substantially better than "try all possibilities", which is where we are now.

It's uncertain what complexity class factorization in, but the best known techniques are not in P. P=NP therefore implies there is indeed a 'better' factorization algorithm. And so, you can crack encryption faster.

So much confusion here. You are correct that P=NP is theoretically relevant to factorising numbers because, as you point out, factorising numbers is somewhere between P and NP, so if P=NP then factorising is also P. The OP is correct first that complexity theory isn't terribly relevant to cryptography because considerations of worst case or even average case complexity say nothing about any specific key - you have no way to prove that the key you've got is actually worst-case. Complexity theory is never dir

Cracking a key is NP hard, and with sufficiently large keys you can not amass enough computing power to crack them. If you can convert it to a P problem the computing time is reduced to practical dimensions. I think this film is about a sidestep ('melt the sand') that converts NP problems to P problems.

He probably made the mistake lots of people make, which is to think "NP hard" is similar to saying "rocket-science hard", where NP is just an adjective describing "hard". People don't realize that "NP-hard" is itself a formal class of problems that is not necessarily equivalent to NP. It's not his fault... its a horribly confusingly named set of concepts.

Secret-Key cryptography - the traditional stuff like DES or AES, where you use the same key to encrypt and decrypt a message - typically doesn't use algorithms that would be affected by a constructive proof that P==NP. They're basically designed around complex messy mixing systems, not around hard math problems that would be simplified by a P=NP solution.

Public-Key cryptography, of course, is all about hard math problems, though it turns out that NP-complete problems like knapsacks don't usually have the r

Which is why one-time-pad wouldn't work. But for any of the other "real-life" cryptosystems, manipulating the input to provide another viable decryption key with a chosen output would effectively mean cracking the system anyway.

You are talking about brute force, high bound on the work required to crack something. Any respectable encryption algorithm sets these reasonably high (like, use all computers on earth for thousands of years...). The problem is there may be shortcuts revealed thru cryptanalysis based on some properties of the cipher. And these are extremely valuable to certain people/agencies if they remain secret... these may involve such class of a problem. I can see a lot of material for a thriller plot there...

Cryptography relies on problems that are very hard to solve without a key, but when you have the key are easy. NP problems have the property that if you know the solution, it's easy to prove that you have the solution, but finding a solution is otherwise really hard. Take factoring for example, which is an NP problem - take two really big primes, and multiply them. Give the result away to anyone who asks. If the primes are big enough, they won't be able to figure out your original primes, but anyone who has either of the original primes can find the other with ease. RSA is dependant on that property. If I can find those two primes quickly from just public key, I've cracked RSA. If NP=P, then factoring is no longer a hard problem.

IANAC but just what I remember from my CS degree, factorization is NP-complete, if it can be simplified to polynomial then maybe it's easier to crack something (public key systems that rely on the complexity of factorization like RSA) ? Shor's algorithm [wikipedia.org] that works on a quantum computer does make it polynomial and it says in the link that it will have major implications to security schemes that rely on factorization (such as RSA).

I wonder if this movie is related to that (transforming sand to glass could

Factorization is most likely not NP complete. Rather, it is in the intersection of NP and coNP, and it is widely believed that no NP complete problems are in coNP, for reasons similar to the reasons it is believed that no NP complete problems are in P. It is also unlikely that there is a "complete" class for the intersection of NP and coNP, which casts some doubt on the hardness of integer factorization.

Of course, if P=NP, integer factorization is definitely a theoretically feasible problem; this does not mean that it can be easily solved in practice, though. Maybe the best algorithm for integer factorization runs in O(n^100) time -- polynomial but still beyond the reach of any reasonable computer. P=NP would not imply that cryptography is impossible; rather, it would require some new definitions of security and entirely different approaches to cryptography.

Secret-key crypto isn't dependent on NPish-hard problems, just on complex messiness, and it'll work fine even if we've got magic quantum computers. We'd have to go relearn all of those annoying Key Distribution System methods that public-key replaced, figure out what if anything to do about signatures, and have to build a whole lot of new business models for dealing with trust, since we'd have to actually trust the people running the KDC, but we'd live.

Secret-key crypto isn't dependent on NPish-hard problems, just on complex messiness, and it'll work fine even if we've got magic quantum computers. We'd have to go relearn all of those annoying Key Distribution System methods that public-key replaced, figure out what if anything to do about signatures, and have to build a whole lot of new business models for dealing with trust, since we'd have to actually trust the people running the KDC, but we'd live.

This is not quite right. Secret key crypto will be fine if quantum computing becomes ubiquitous (or if we find out that P=BQP), but P=NP is a vastly more powerful result, to the extent that it would shatter secret key crypto as well. P=NP means that you can pluck answers to a question out of the aether with no more difficulty than checking if one random input answers the question. So if you know how to calculate "lambda key: ciphertext.decrypt(AES, key).matches(English)", then by P=NP magic you already k

In cryptography you're looking for a problem that is asymmetric. NP is your ideal, but as a lot of other people have pointed out, practical cryptographic algorithms are a not ideal. IBM actually had a cryptography algorithm based on the TSP once, but they must have found a flaw because it was never popularized.

A lot of people confuse NP and/or 'intractable' with 'impossible'. They do not mean the same thing. Intractable problems are often practically impossible, if for instance it would require more mass than the entire universe to calculate the answer. But since our understanding of physics is incomplete, we can't say for sure how big a 'perfect' computer you'd need to solve a certain problem, so you can't categorically say that it's impossible. All you can say is "we can't do it today." or "That's a problem for my grandchildren to deal with... hopefully."

Remember that for certain inputs an NP-Complete problem can be solved on the back of an envelope. If I tell you to place a dot in the middle of the envelope, and one more or less near each corner, you can find the shortest path in a few minutes. It's an NP complete problem, but it's still trivial to solve. NP is not a magic wall. It all depends on the context (ie, the inputs).

IBM actually had a cryptography algorithm based on the TSP once, but they must have found a flaw because it was never popularized

There are cryptosystems based on [wikipedia.org] the knapsack problem, which is also NP-complete. (The basic idea is that your private key is a super-increasing set like 1,2,4,8... -- a special case for which the knapsack problem is easy -- but you disguise it via modular arithmetic as a plain ol' hard-as-fuck knapsack knapsack problem)

But like with (what you say of) the IBM/TSP cryptosystem, they always seem to get broken -- not universally breakable, but commonly-breakable enough to fail crypto standards. I can't remem

You forget that there is no way to decide in polynomial time if the text you got is the plaintext. That's why the one-time pad is provably secure: Every text of the same length could be the plaintext, and without knowing the key, you cannot distinguish between "Attack tomorrow 10:00" and "We should surrender!!"

You forget that there is no way to decide in polynomial time if the text you got is the plaintext.

Actually there is a way to tackle that issue. A plaintext is typically highly compressible, while a failed decryption is effectively random. There is there is a statistically zero probability for any failed decryption to be as compressible as the true text. So you reformulate the problem as "What password returns the shortest length when decryption AND compression are applied". If by sheer fluke you do get a junk password yielding a garbage result, you can simply try again asking for the password that retur

This technique yields the interesting result that you want to apply an optimal compression algorithm to your files before encrypting them. That way you are encrypting effectively random data, so that an attacker cannot use this sort of method to identify a successful decryption.

Except applying the corresponding decompression after decryption, of course.

You don't have the decryption yet. You need an algorithm to obtain a potential decryption. If P=NP then you can use an algorithm to (relatively quickly) find and give you the most compressible decryption. And the most compressible decryption is almost certainly the correct decryption. If the message is already compressed then you need some other way for an algorithm to pick out what potential decryption to give to you. For example if you know a specific name probably appears in the true text then you could

The P=NP aspect is just geekiness. You didn't solve it, and the movie had better not be about solving it. That would be stupid.

You can, however, make a thriller using that as a MacGuffin. The better you know the math, the more rich-sounding the dialogue around the MacGuffin will be, but it must remain a MacGuffin. It's the Lost Ark from Raiders, or the Maltese Falcon. Either is a fine thriller, with interesting characters and snappy dialogue.

This really annoys me. You can't accept that they're white by chance? As in, they just happened to cast those actors? Having worked in the advertising industry (shudder) I can tell you how MADDENING it is when you've got a bunch of really good takes or photographs but you've got to discard them because you've been told by some bleeding heart retard that you need that one minority in there, who just so happens cannot pose in front of a camera to save their life. This leads to lots of post processing and othe

I'm genuinely not sure how to exactly one's mind would have to work to even have noticed this without somebody else mentioning it to them (which in turn would raise the question of where the previous person heard it, and so on... where the causal chain ultimately reveals one sick-minded puppy).

Do you ordinarily go out of your way just to correlate any kind of entirely coincidental absence of a minority with the implication of deliberate racism, or is this just a one-time thing?

Do you ordinarily go out of your way just to correlate any kind of entirely coincidental absence of a minority with the implication of deliberate racism, or is this just a one-time thing?

There are people for whom that is profession - folks who make six figures noticing that, spinning up faux outrage, and holding people hostage for cash over it. Don't be surprised that it's also some other people's hobby, and the lens through which they look at everything.

The phrasing of the statement appears to imply a rather disgusted tone, which, in turn, implies that some sort of unspoken racist intent must have been at work.

It's not like I was the only one who read his statement as some sort of notion that he was suggesting that the makers may have been biased against certain people based on the color of their skin... and while I realize that such appeal to the majority does not necessarily make me right, it does seem to make my conclusion one that it is not unreason

I often wonder why people invoke racism so often when it comes to these issues when the reality is... disadvantaged white kids often fare pretty poorly too. If one of your strongest indicators, do you really need race to explain why, generation after generation, racial dmeographics shift less than we "would like".

Yes the smartest in this society are probably mostly a bunch of white guys. Not because being white makes you better, or smarter, but because there are more white people who can give their children the opportunity to advance. Which isn't to say that being white people gave them that ability, but just that, the "initial condition" that we started with has done more to influence the outcome than we want to give it credit.

In short, I often feel racism is used as an excuse to deny the lack of real mobility within society....because if you don't think race/genetics is a major factor, then how do you explain the "lack of progress" along racial lines, if there is very high mobility? Seems to me it may be the lack of real mobility.

I often wonder why people invoke racism so often when it comes to these issues when the reality is... disadvantaged white kids often fare pretty poorly too. If one of your strongest indicators, do you really need race to explain why, generation after generation, racial dmeographics shift less than we "would like".

Yes the smartest in this society are probably mostly a bunch of white guys. Not because being white makes you better, or smarter, but because there are more white people who can give their children the opportunity to advance. Which isn't to say that being white people gave them that ability, but just that, the "initial condition" that we started with has done more to influence the outcome than we want to give it credit.

In short, I often feel racism is used as an excuse to deny the lack of real mobility within society....because if you don't think race/genetics is a major factor, then how do you explain the "lack of progress" along racial lines, if there is very high mobility? Seems to me it may be the lack of real mobility.

The lack of real mobility is a myth. I can say this because I come from a family that emigrated and came to the United States and started off on welfare, living in government projects, and going to very poorly supported schools. What made the difference for me were parents to valued education and pushed their kids to go beyond what was considered average. They convinced me, my siblings, and themselves, that the government handouts were temporary aids for us, and that continuing to live off the government when we have the ability to eventually make it on our own is shameful. My parents were farmers and made it as far as completing elementary school back in their homeland. So it isn't as if they had a great start, either. Yet my siblings and I, on the other hand, completed college, and I completed my Ph. D. in mathematics -- and we all went through public schools prior to college. If I were an exception, then we might call it "lack of mobility." The problem I see is that our government has made it too easy for those who have to rely on its social programs to do it for so long. For many, it is much easier to accept a very modest, but not-uncomfortable lifestyle of welfare and food stamps rather than to make an honest effort to move out of their current conditions.

Many immigrants who come to the US will have very similar stories of how they or their parents moved to the US with hopes of finding better opportunities. They often come from places where the conditions are so terrible that even the living in government projects and relying on the US welfare system is heavenly in comparison. Yet they do not fall into the welfare trap and eventually contribute to society like the rest of US citizens who were born and raised here. What they have that a lot of folks who are "stuck on welfare" is a drive. In my own parents' case, what drove them was their belief that if they could escape a communist government (that sought to execute anyone who defied it) by risking everything on a 2-piston boat set off into unknown waters, then they can certainly get out of welfare. This drive is lacking in a lot of families who are currently relying on government programs (I'm referring to families in which welfare reliance occurs for generations).

I didn't say there is no mobility, just that it is less than we would like. Even with very little mobility, you will always have edge cases.

Also, there are more issues than just being poor. If I were placing odds, I would give a person from a poor family with well educated parents much better odds than someone from a reasonably better family with uneducated (and I don't mean grade level completed so much as equivalency... I mean ability to read/write/do basic math maybe some algebra)

It would be a big mistake to assume that the opportunities available for Cuban-American immigrants in Miami (which is what I'm guessing you are based on your post) are identical to the opportunities available for African-Americans in the worst neighborhoods in Detroit. I'm not saying drive doesn't count, but in order to succeed a person needs both drive and opportunity. Someone with no opportunities can't succeed no matter how much they're driven to do so.

Hardly - the United States is on par with petty dictatorships [guardian.co.uk] for income inequality and mobility. A young member of the working class can look forward to graduating with $25k or more in student loan debt and then struggling to find a job in a shitty economy while hoping they don't need health care. Whereas the rich don't have to worry about health care or student loan debt or housing and can afford to take a year long unpaid internship - or three - before getting a job.

I think you are the one missing the point. The context of the discussion was about character placement in a film thats supposed to take place HERE. What goes on in other places doesn't matter in this context, in fact, its explicitly irrelevant.

I disagree with this statement. Intelligence is mostly controlled by your genes, it isn't even disputed in the science community. Has nothing to do with how you were raised. There's a bunch of studies on adopted kids and twins that were raised apart. No one ever likes to talk it about because for certain reasons i won't bring up because this type science has been used to commit some of worst crimes against humanity in modern history. Also IQ doesn't mean successful, being successful has to do with y

I disagree with this statement. Intelligence is mostly controlled by your genes, it isn't even disputed in the science community. Has nothing to do with how you were raised.

"mostly controlled by genes", probably. "nothing to do with how you were raised", not true. The reason that the twins/adoption studies evidence isn't more widely discussed is that it is of zero practical use -- it tells us people are different, but it gives us no insight into how to identify or deal with different types of people.

A medical analogy (I don't drive, so I don't do car analogies).

There are two diseases. One won't kill you unless you attempt to treat it with aspirin. One will kill you unless y

I also don't know what studies you're reading. The ones I've read reach nearly the opposite conclusion. So at best we could chalk this up to 'science in the field is unclear'.

Nor do I know where the AC was getting his info, but he's right and you're wrong. IQ is highly heritable. WP has a detailed article [wikipedia.org] on this.
Reference 7 in the WP article is to a 2004 meta-analysis that puts the heritability figure at about 85% (meaning that heredity explains about 85% of the variance in adult IQ).

I also don't see what this has to do with the movie. There is a very simple explanation for the fact that, for example, most Nobel prize winners are white. It's because access to education is h

Nor do I know where the AC was getting his info, but he's right and you're wrong. IQ is highly heritable. WP has a detailed article [wikipedia.org] on this.
Reference 7 in the WP article is to a 2004 meta-analysis that puts the heritability figure at about 85% (meaning that heredity explains about 85% of the variance in adult IQ).

Correlation is not causation. Latest news from the causation camp is that they have found the "intelligence gene". However, they say it's only responsible for 1.29 IQ points [gizmodo.com.au]. That's 1.29% , not 85%.

Some of these are studies of twins raised separately by people other than their biological parents, which basically makes them immune to this objection.

Latest news from the causation camp is that they have found the "intelligence gene". However, they say it's only responsible for 1.29 IQ points. That's 1.29% , not 85%.

Nobody is claiming they've found "the" gene for intelligence. You seem to be misinterpreting what you've read, or maybe what you've read is a popularization that misinterprets the science. The fact that a particular gene only explains a small amount of variance doesn't mean what you seem to assume it means, which is that there are no other genes affecting in

Your question is irrelevant since it didn't happen that way. The movie was filmed in a country that claims to be a melting pot and yet the "4 smartest ppl in the world" are a bunch of skinny white guys.

You're talking about an extremely small set. Let's reduce it further to just one: "The smartest person in the world". Now are you going to be upset if this person isn't representative of every culture?

Admittedly, this may be the result of my Western upbringing, but I think it might be accurate to portray the greatest living mathematicians as white -- with possibly an Indian or Asian or two. For the past few hundred years, most of the greatest mathematicians [fabpedigree.com] have been skinny white guys*. If you go back to the foundations of algebra, you do find some Persians (arguably "white") and some Indian guys. Given that the movie appears to be a US-centric one, it would have been pretty easy to throw in an Asian/Ind